The Canadian border with the United States has come under renewed scrutiny following Tuesday's announcement that Canada would slow down its ambitious plan to welcome 25,000 Syrian refugees. The plan, aimed at resettling the refugees by the end of the year, has been extended to February.

Critics have argued that the border connecting the U.S. with Canada is a hotbed for illegal immigration and is much more of a threat to allow potential terrorists, such as the so-called Islamic State militant group, into the U.S. than the nation's southern borders with Mexico.

"If somebody is set on doing it, there are plenty of opportunities to cross this border," U.S. Border Patrol agent Andrew Herdina told Reuters while standing in Havre, Montana, near that state's 500-mile border with Canada. The U.S. has said it will resettle up to 10,000 Syrian refugees by next year.

There are 18,000 border patrol agents monitoring the U.S.'s southern borders, while there are just 2,200 along the border with Canada, which stretches 5,500 miles from Alaska to Washington and Maine, according to Reuters.

Newly sworn in Canadian Prime Minister Justin Trudeau tweeted Tuesday afternoon that Canada still has plans to host Syrian refugees as quickly as possible, but his country would take its time doing it. Trudeau's announcement coincided with a heightened global focus on the resettling of Syrian refugees and the accompanying worry of some that a section of the apparent asylum-seekers could actually be terrorists looking to attack sites in North America.

ISIS, which has claimed responsibility for a fresh series of terror attacks across the globe, most recently in Paris, last week used the latest issue of its magazine to call for terror attacks to be launched in Canada, reported the Toronto Sun. 

The militant group that largely operates out of Syria prompted one Canadian official to warn his countrymen over what the future could bring, especially following the Nov. 13 terror attacks in Paris that killed 130 people and left hundreds more injured.

“I would urge Canadians themselves to be alert in the wake of these very troubling circumstances,” Canadian Public Safety Minister Ralph Goodale said last week.

Still, Canada was expecting to receive the refugees, as evidenced by ongoing preparations at various Canadian military bases. "We've been asked to look at our options, our accommodations and so on, like the numbers," Capt. Evelyne Lemire, a spokeswoman at Canadian Forces Base Gagetown in New Brunswick, told Canadian news outlet CTV News. "We're ready to receive any Syrian refugees, if we're called on to do that."